Various forms of processing with ionized gases, such as plasma etching and reactive ion etching, are increasing in importance particularly in the area of semiconductor device manufacturing. Thus, the investigation of the effects of the variation of various process parameters defining a plasma process has been pursued. Of particular interest are the various etching processes used in semiconductor device manufacturing. It is increasingly necessary to produce very fine lines with such processes, which requires a high degree of process uniformity, flexibility and control. A further need exists for apparatus which provides efficient wafer handling.
As disclosed in U.S. Pat. No. 4,464,223, it has been discovered that a plasma reactor which is capable of applying power of more than one frequency to energize the plasma offers significant advantages in terms of process flexibility, control, and uniformity. However, the advantages of such a dual frequency process have only been achievable in multi-electrode plasma reactors. Such reactors are structurally more complex and therefore may be commercially disadvantageous in some circumstances.
A particular need exists in the area of metal etching processes. In order to achieve the desired end result, it is necessary to adequately remove any organic and/or inorganic residues from the etched surface. Prior art etching processes have proved lacking in one respect or another in providing an adequately clean surface following a metal etching step.